The striate cortex of one hemisphere is removed surgically from rhesus monkeys under direct vision, and the monkeys are allowed to recover from the effects of surgery in a normally lit environment. The monkeys are then trained on a series of tasks requiring visual perception and visually-guided eye movements. They are then prepared for chronic neurophysiological recording, and the activity of single neurons in the posterior parietal cortex both ipsilateral and contralateral to the lesion is studied. Preliminary results indicate that the great bulk of the parietal cortex has its visual responsiveness to stimuli contralateral to the damaged hemisphere eliminated. However, several cells in small areas of the parietal cortex maintain responsiveness to both visual fields. This indicates that visual activity in the posterior parietal cortex is partially dependent upon an intact visual cortex but that some visual information can reach the parietal cortex exclusively through the extrageniculostriate pathways. These islands of maintained visual activity presumably subsume the surprisingly large residual visual capacity found in monkeys and man with damaged striate cortex.